Circuit breaker



Nov. 5, 1929. w. M. AUSTIN 1 CIRCUIT BREAKER Filed April 13. 1922 2 Sheets-Sheet 1 WITNESSES: I v INVENTOR" facmfi. Wa/IrMHusTfiI. Km BY ATTORNEY I V- 1929- p w. M. AUSTIN 1,734,190

CIRCUIT BREAKER I Filed April 13. 1922 I 2 Shuts-Sheet 2 WITNESSES: I INVENTOR ATTORNEY Patented Nov. 5, 1929 UNITED STATES PATENT OFFICE WALTER M. AUSTIN, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA CIRCUIT BREAKER Application filed April 13,

My invention relates to circuit breakers and particularly to operating mechanisms therefor.

One of the objects of my invention is to provide an improved means for moving the bridging member of a circuit breaker to closed position and for releasably maintaining it in such position, one feature of the invention residing in the provision of toggle mechanism for closing the breaker having such formation that it functions as a latch for maintaining the breaker in closed position.

Another object of my invention is the pro vision of improved means for controlling the circuit through an operating coil that is connected in shunt relation to the main circuit.

Another object of my invention is the provision of an improved formation of calibrating device whereby the trip coil of an automatic circuit breaker is permitted to become effective only under predetermined conditions.

A further object of my invention is to simplify the construction of circuit breakers generally and to lessen the cost thereof.

As shown in the accompanying drawings,

Figure 1 is a View, partially in side elevation and partially in section, of a circuit breaker that embodies my invention;

Fig. 1a is a fragmentary detail View of certain of the parts of the device shown in Fig. 1;

Fig. 2 is a view similar to that of Fig. 1, showing certain of the parts in open position;

Figs. 3 and 4 are elevational views of the latch spring which I employ in my invention' Figs. 5 and 6 are plan and side elevational views, respectively, of one of the link members embodied in my invention;

Figs. 7 and 8 are views of another link member embodied in my invention;

Fig. 9 is a view, in side elevation,-of still another link member that co-operates with the link members of Figs. 6, 7, and 8;

Fig. 10 is a view of the operating lever embodied in my invention;

Figs. 11, 12 and 13 are plan, side elevational and front elevational views, respec- 1922. Serial No. 552,149.

tively, of a portion of the tripping mechanism which I employ, and

Fig. 14 is a View illustrating, diagrammatically, the manner in which the trip coils are connected in the circuit that is controlled by the circuit breaker.

The apparatus comprises a panel 16 to which are secured terminal members 17 and 18 that are connected to the stationary contact members 19 and 20, respectively, a bridging contact member 21, and arcing tips 22 and 23. As thus far described, the apparatus may be of any standard form.

The bridging member 21 is pivotally mounted at 25, between brackets 26, only one of which is shown. An operating lever 27 is also pivotally mounted between the brackets 26 and is provided with a handle 28 and lugs 27a that engage lugs 260 on the brackets, to limit the downward movement of the handle 28. The lever 27 is provided with a pair of openings 29 through which a pin 30 extends to serve as a pivot therefor.

The lever 27 is provided, also, with a pair of openings 24 (Fig. 10). When the apparatus is in assembled relation, the openings 24 are in alinement with a pair of openings 31 which extend through a link member 32 that is pivoted at 33 to a supporting member 34 for the bridging member 21. A pin 35 extends through the openings 24 and 31.

An intermediate link member 37, shown more clearly in Figs. 7 and 8, is provided with openings 38 and 39 therethrough. The portion that is provided with the opening 39 extends into the recessed portion of the link 32 (Fig. 5) and the openings 39 aline with the openings 31, the pin 35 serving as a pivot member for the lever 27, link 32 and link 37.

It will be observed that the link 37 is cut away at its interior, as shown in Figs. 7 and 8, to expose a portion of the pin 35 for engagement with a link 40, as hereinafter described.

The link member 40 is provided with an extended portion 41 and an opening'42. The extended portion 41 occupies a position within the cut-out portion of the link 37, and the hole 42 alines with the openings 38 of the link member 37, a pin 44 being provided to serve as a pivotal connection between the link members 37 and 40. In the closed position of the circuit breaker, the portion 41 of the link 40 bears against the pin 35.

Atits lower end, the link 40 is provided with a hole 45 through which a pin 46 extends, the pin also extending through the brackets 26 to provide a pivotal support for the link 40. A

A tripping plate 48 is also pivotally supported by the pin 46 and has its rear portion 49 normally in abutting engagement with a portion of the bracket 26, to limit the downward movement of the shelf-like extension 48a of the tripping plate 48.

It will be observed that the extended portion 51 of the link 40 normally lies directly above the extension 48a of the member 48 (see Fig. 1).

A spring 54, with openings 55 therethrough, (Figs. 3 and 4) is supported by the pin 44, and its extended portions 56 are disposed downwardly and abut against the inner side of the pin 46. A yoke portion 57 of the spring 54 extends across the rear edge of the link 37. The spring 54 is maintained under tension and biases the pin 44 and the link 40 inwardly to the position shown in Fig. 1.

In the closed position of the switch, as illustrated in Fig. 1, the bridging contact member 21 is normally biased outwardly, both by means of its inherent resiliency and by means of a tension spring 58, but is maintained in closed position by means of the toggle arrangement, which will now be described.

The reaction of the bridging member to the tension imposed thereupon is against the link 32 and the operating lever 27, and also against the links 37 and 40, by reason of the fact that the pin 35 is out of alinement with the pins 33 and 30. This offset relationship of the pins tends to cause the pin 35 to move downwardly to permit the bridging member 21 to move to its open position. However, the tendency toward collapsing movement downwardly is resisted by the links 40 and 37. The pins 35, 44 and 46 are in substantial alinement when the breaker is in closed position, and the pressure exerted by the spring 54 upon the rear edge of the link 37, and the consequent reaction thereof upon th pin 35, prevents the collapse of the toggle mechanism. It will be noted that these pressures tend to produce clockwise rotation of link 37.

Upon a slight upward movement of the inner end 4860 of the tripping plate 48, either through the medium of an automatic tripping mechanism, which will be hereinafter described, or manually by the plunger 60 that bears against the portion 49, the link 40, by reason of the consequent engagement of the plate with the extension 51, is moved slightly about its pivot 46, against the tension of the spring 54. This movement carries the pin 44 outwardly a suflieient distance to cause the downward pressure exerted through the link and the pivot 35 to overcome the tension of the spring 54, thereby collapsing the toggle mechanism and permitting the bridging member 21 and the operating lever 27 to move to the positions illustrated in Fig. 2.

A bolt 59 is provided in order that an interlocking bar (not shown) may be supported thereby so that adjacent breakers may be automatically tripped upon the tripping of the brea er here shown. The hole 42 in the link 40 is elongated to provide lost motion between the bracket 49 and the handle, so that during manual operation of the breaker an adjacent breaker may be tripped notwithstanding its rigid connection by the said bar and bolt 59 to the bracket 48.

Starting with the parts in the positions of Fig. 2, the handle 28, ii depressed, will canse the rotation of the operating lever about the pivot 30, thus imparting, through the pin 35 and the link 32, a closing movement to the bridging member 21 and the arcing tips that are carried thereby. When the parts have reached approximately the position illustrated in Fig. 1, the spring 54 will cause the link 40 to move to its seat against the pin 35, to render it and the link 37 again effective as looking members.

Referring now more particularly to Fig. 1, I provide coils 62 and 63 that co-operate with a movable core member 64 to effect automatic operation of the switch under predetermined conditions in the circuit. In the present instance, I will describe the coil 63 as a low-voltage coil and the coil 62 as a current coil.

The purpose of these coils is to cause automatic tripping of the circuit breaker, upon either a reversal of current or upon the falling of the voltage below a predetermined amount. .Vith the circuit breaker in closed position, the coils 62 and 63 are normally energized to maintain the movable core mem ber 64 in its lower position. against the compression of a spring 66. The core member 64 is provided with a stem 67 that extends downwardly and is engaged by the upper end of a rod 69 which carries a collar 68 that abuts against the spring68. The rod 69 is provided with a squared shank portion 69 that extends through a squared opening in the bottom of a chamber 70, so as to be non-rotatable with respect thereto.

A sleeve-like member 61 serves as a guide for the rod 69 and the core member 64.

vhould the voltage through the coil 63 fall below a predetermined amount or the direction of current through the coil 62 be reversed, the magnetic force exerted upon the core member 64 would be so reduced that the core 64 would move upwardly under the im pact of the rod 69 when acted upon by the spring 66, and trip the breaker through the medium of the tripping plate 48.

A second spring 72 is disposed between the spring 66 and the shank 69 of the plungerrod 69. This spring 72 is preferably made of greater stiffness than the spring 66, the purpose bein to effect adjustment of the device so that it may be set to trip under various degrees of changes in the circuit. The chamber is provided with. a thread on the exterior thereof that engages a helical groove on the inner surface of a supporting bracket 73. By loosening a set screw 75%, the shank 69 of the movable core member may be rotated to move the chamber 70 either upwardly or downwardly along the inclined grooves of the brackets 73.

If the chamber 70 be moved upwardly, the lower ends of the springs 72 and 66 are, of course, carried with it. The parts may be thus moved a distance sufficient to bring the upper end of the spring 72 to a position where it will be more or less forcibly engaged by the reduced portion of the collar 68 when the movable core member 64is drawn down into its normal position within the coils 62 and 63. The vertical adjustment of the spring-supporting chamber 70 determines the magnetic force required to hold the movable core member 64 in its lower position against the tension of the springs 66 and 72.

IVhile the device may function effectively with the employment of but one of the springs 66 and 72, I find it desirable to employ the spring 66 merely as an actuating spring for moving the core member to its upper, or tripping, position when current conditions through the coils 62 and 63 undergo a predetermined change, and the calibration is effected by positioning the spring 72. If the core member be drawn down against the pressure of both springs, a change in the current conditions, While not suflicient to permit the spring 66 to operate, the core member 64, may, under predetermined conditions, permit the core 64 to be started on its upward movement by the pressure of the spring 72, and such movement will be completed by the spring 66.

A leaf spring 76 is secured to the frame 77 of the coils at its one end, and its othe end carries a bridging member 78 for closing a circuit through a pair of contact members 79 (Figs. 1 and 14;). The member 78 is insulated from the spring 76. The spring 76 is in position to be engaged by the upper side of the collar 68 when the core member is moved to trip the breaker, the purpose being to open the circuit through the coil 63 when the breaker is in its open position.

In Fig. 14 I have shown, diagrammatically, the means by which the current or shunt coil 63 is connected across the main circuit and the manner in which the low-voltage coil 62 is connected in the circuit. The coils and the connections therefor are of somewhat the usual form and are shown in order to more clearly illustrate my invention.

Various modifications and changes may be made in the invention without departing from the spirit and scope thereof, as defined in the accompanying claims.

I claim as my invention:

1. A latching mechanism for maintaining a movable member in a predetermined position which comprises a pair of link members arranged as a toggle joint, a second toggle joint for maintaining the first named joint in under-set position, pintles for the toggle joints, and means whereby the pintles of the second named toggle are maintained in substantial alinement comprising a resilient member cooperating with two links of the toggle and supported by their common pintle.

2. A latching mechanism for maintaining a movable member in a predetermined position which comprises a pair of link membcrs arranged as a toggle joint, a second toggle joint for maintaining the first named joint in underset position, pintles for the toggle joints, and means whereby the pintles of the second named toggle are maintained in substantial alinement comprising a coiled s1 ring cooperating with two links of the toggle andsupported'by their common pintle.

The combination with a circuit breaker, of a tripping member therefor, normally maintained under the action of magnetic forces in retracted position, a spring nor mally tending to move the said member against the action of the magnetic forces and a second spring supplementing the first named spring, the second mentioned spring serving to move the tripping member for a portion only of its normal movement and the first named spring serving to advance the tripping member to its final tripping position.

4. The combination with a circuit breaker, of a tripping member therefor comprising a magnetizable member, a spring for normally biasing the said member toward tripping posit-ion, an clectromagnet for normally maintaining the said member in retracted posi- 'tion against the compression of the spring, and a second spring supplementing the opposing force of the first named spring, the

lirst named spring being adapted to move the magnetisable member to tripping position when the force of the electromagnet falls below the combined forces of the said springs.

5. The combination with a circuit breaker, of a tripping member therefor comprising a magnetiZab-le member, a spring for normally biasing the said member toward tripping position, an electromagnet for normally maintaining the said. member in retracted position against the compression of the spring, and a second spring supplementing the opposing force of the first named spring, the. first named spring being adapted to move the magnetizable member to tripping position when the force of the electromagnet falls below the combined forces of the said springs, and calibrating means for adjusting the positions ot' the springs with respect to the electromagnet.

6. In a circuit interrupter, a plunger of magnetic material, coils for controlling the position of the plunger, and means for biasing the plunger to another position comprising a pair of helical springs of unequal length surrounding and engaging the plunger.

7. In a circuit interrupter, a plunger of magnetic material, coils for controlling the position of the plunger, means for biasing the plunger to another position comprising a pair of helical springs of unequal length surrounding and engaging the plunger, and a movable casing engaging the helical springs for controlling their tension.

8. The combination with a circuit interrupter, of tripping means therefor comprising a solenoid and a movable core, actuating means for said core comprising biasing means active on said core through substantially the entire path of movement of said core and a second biasing means active on said core through only a portion of said path.

9. In combination with a solenoid and a movable core, actuating means for said core comprising biasing means active on said core through substantially the entire path of movement of said core, and a second biasing means active on said core through only a portion of said path.

10. The combination with a circuit interrupter, of tripping means therefor comprising a solenoid and a movable core, actuating means for said core comprising a spring active 011 said core through substantially the entire path of movement of said core and a second spring active on said core through only a portion of said path.

11. In combination with a solenoid and a movable core, actuating means for said core comprising a spring active on said core through substantially the entire path of movement of said core and a second spring active on said core through only a portion of said path.

12. A mechanism comprising a solenoid, a movable core member, a calibrating element and a pair of biasing springs for said core member, one of which is tensioned during the entire path of travel of the said core men1- her, the other tensioned over the length of the calibration range.

In testimony whereof, I have hereunto subscribed my name this 10th day of April, 1922.

WALTER M. AUSTIN. 

